Inside Costco’s Secretive Retail Media Strategy: What Mark Williamson Revealed

Costco has always been the effortlessly cool kid of the retail media world: unbothered by hype, quietly confident, and doing things entirely on its own terms. In this episode, I unpack what makes Costco’s retail media approach so different from the 80+ U.S. retail media networks vying for attention, and why their “member-first, margin-second” philosophy is more than just a tagline.

After digging through Mark Williamson (Retail Media AVP at Costco) interviews, I piece together a clearer picture of how Costco is building a retail media business that deeply aligns with its culture, elevates member value, and defies the standard playbook. I explore their unique team structure and ruthlessly disciplined data foundation, as well as the philosophical stance that guides every media decision they make.

This episode is sponsored by Mirakl Ads

Timeline

[00:19] – Why Costco avoids the splashy retail media hype and plays the long game
[02:53] – Mark Williamson explains why “monetization” isn’t even in Costco’s vocabulary
[04:47] – The uncompromising member-first philosophy and how it blocks “free money”
[07:15] – How Costco’s Growth Management Team bridges merchants and media
[09:00] – Why retail media revenue is immediately reinvested into merchandising
[10:10] – The power of 100% member-identified transactions and deterministic data

Links & Resources

• This episode expanded on my recent article for The Drum - Costco: the retail media network that refuses to promote itself
• The Commerce Collective full episode with Mark Williamson - Putting Members First: How Value Guides Costco’s Retail Media Vision
• The CPG Guys full episode with Mark Williamson - Media that Drives Retail Sales with Costco’s Mark Williamson
• Follow Mark Williamson, Retail Media AVP at Costco, on LinkedIn
• Read my articles:
  • The ‘How Brands Grow’ Dogma Wants To Have A Word With Retail Media
  • How Can RMNs Tap Upper-Funnel Brand Budgets
• I'll be diving into the findings of the Pentaleap H2 2025 Sponsored Products Benchmark report with Pentaleap co-founder and CEO Andreas Reiffen on Thursday December 4 at 11AM ET! Join us LIVE here
• Are you based in Atlanta or plan to be in the ATL area on Weds Dec 3rd? Join me and a couple dozen of your new retail media industry besties for a festive happy hour! Register here
• Subscribe to Retail Media Breakfast Club's daily newsletter
• Follow Kiri on LinkedIn